On 19 Feb 2020, at 23:48, Gleb Smirnoff wrote:
On Tue, Feb 18, 2020 at 10:08:50PM +0100, Kristof Provost wrote:
K> So I suspect our call stack is something like virtqueue_intr() ->
K> vtnet_rx_vq_intr() -> vtnet_rxq_eof() -> vtnet_rxq_input() ->
K> ether_input().
K> I don’t see anything entering epoch in that path, which
presumably explains
K> the panic, but I still don’t understand why my bhyve current vm
doesn’t
K> panic in the same way.
On bhyve we enter it through interrupt handler, and this is where we
enter the epoch. Does RISC-V has interrupt handling by the MI code
in sys/kern/kern_intr.c as other platforms?
It does, yes, but that was the hint I needed. I didn’t know that we
entered net_epoch automagically based on the interrupt type.
The difference between the two is that Bhyve uses virtio_pci, and in my
qemu case we run through the virtio_mmio path. In that path we always
set INTR_TYPE_MISC, so we never set INTR_TYPE_NET, even for if_vtnet, so
we never entered epoch.
This is the correct fix:
diff --git a/sys/dev/virtio/mmio/virtio_mmio.c
b/sys/dev/virtio/mmio/virtio_mmio.c
index 95eb8647052..ccafe326868 100644
--- a/sys/dev/virtio/mmio/virtio_mmio.c
+++ b/sys/dev/virtio/mmio/virtio_mmio.c
@@ -196,7 +196,7 @@ vtmmio_setup_intr(device_t dev, enum intr_type
type)
return (ENXIO);
}
- if (bus_setup_intr(dev, sc->res[1], INTR_TYPE_MISC |
INTR_MPSAFE,
+ if (bus_setup_intr(dev, sc->res[1], type | INTR_MPSAFE,
NULL, vtmmio_vq_intr, sc, &sc->ih)) {
device_printf(dev, "Can't setup the interrupt\n");
return (ENXIO);
Thanks for the help!
Regards,
Kristof
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